Delta Electronics Series DNS manual Sequential Start-up, Ratio-Metric

FEATURE DESCRIPTIONS (CON.)

Sequential Start-up

Sequential start-up (Figure 40) is implemented by placing an On/Off control circuit between VoPS1 and the On/Off pin of PS2.

Ratio-Metric

Ratio–metric (Figure 42) is implemented by placing the voltage divider on the TRACK pin that comprises R1 and R2, to create a proportional voltage with VoPS1 to the Track pin of PS2.

For Ratio-Metric applications that need the outputs of PS1 and PS2 reach the regulation set point at the same time.

Vin

On/Off

PS1

	Vin
VoPS1	R3
	On/Off
R1
	Q1
R2	C1

PS2

VoPS2

The following equation can be used to calculate the value of R1 and R2.

The suggested value of R2 is 10kΩ.

VO,PS 2	=	R2
VO,PS1		R1 + R2

	Vin
Simultaneous
Simultaneous tracking (Figure 41) is implemented by
using the TRACK pin. The objective is to minimize the	On/Off
voltage difference between the power supply outputs
during power up and down.
The simultaneous tracking can be accomplished by
connecting VoPS1 to the TRACK pin of PS2. Please note
the voltage apply to TRACK pin needs to always higher
than the VoPS2 set point voltage.

PS1PS2

Vin

VoPS1 VoPS2

R1

TRACK

R2

On/Off

The high for positive logic

The low for negative logic

Vin

On/Off

PS1PS2

Vin

VoPS1

TRACK

On/Off

VoPS2

DS_DNS04SIP06A_07172008

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